The present invention relates generally to cooling devices and, more particularly, to a cooling device for removing heat from an electronic device.
Electronic devices, such as integrated circuit devices, are increasingly being used in modern applications. One prevalent example is the computer. The central processing unit or units of most computers, including personal computers, is constructed from an integrated circuit device.
During normal operation, electronic devices generate significant amounts of heat. If this heat is not continuously removed, the electronic device may overheat, resulting in damage to the device and/or a reduction in operating performance. In order to avoid such overheating, cooling devices are often used in conjunction with electronic devices.
One such cooling device is a fan assisted heat sink cooling device. In such a device, a heat sink is formed of a material, such as aluminum, which readily conducts heat. The heat sink is usually placed on top of and in contact with the electronic device. Due to this contact, heat generated by the electronic device is conducted into the heat sink and away from the electronic device.
The heat sink may include a plurality of cooling fins in order to increase the surface area of the heat sink and, thus, maximize the transfer of heat from the heat sink into the surrounding air. In this manner, the heat sink draws heat away from the electronic device and transfers the heat into the surrounding air. An example of a heat sink is disclosed in U.S. Pat. No. 5,794,685 of Dean for HEAT SINK DEVICE HAVING RADIAL HEAT AND AIRFLOW PATHS, which is hereby incorporated by reference for all that is disclosed therein.
In order to enhance the cooling capacity of a heat sink device, an electrically powered fan is often mounted within or on top of the heat sink. In operation, the fan causes air to move over and around the fins of the heat sink device, thus cooling the fins by enhancing the transfer of heat from the fins into the ambient air. An example of a heat sink device including a fan is disclosed in U.S. Pat. No. 5,785,116 of Wagner for FAN ASSISTED HEAT SINK DEVICE, which is hereby incorporated by reference for all that is disclosed therein.
Over the years, as the power of electronic devices has increased, so has the amount of heat generated by these devices. In order to adequately cool these higher powered electronic devices, cooling devices with greater cooling capacities are required. There is also an increasing trend to package electronic devices in multi-electronic device packages. This multi-electronic device arrangement presents an additional challenge with respect to cooling since it results in several heat sources being located within one package. Since each of the electronic devices in the package represents a heat emission source, each must be cooled. In order to adequately cool these multiple electronic device packages, a cooling device must be large enough to contact, or be in close proximity to, all of the electronic devices within the package. Accordingly, cooling devices for cooling such multiple electronic device packages typically are relatively large. Such large cooling device s are problematic in that they are relatively expensive, heavy, and often inefficient.
Another problem with fan assisted heat sink cooling devices is the noise generated by the fans, particularly in situations where larger and/or multiple fans are used to achieve increased cooling capacity. This is particularly a problem in desktop computers where a user is commonly in close proximity to the machine. The problem is further aggravated in situations where multiple electronic devices, and, thus, multiple cooling devices, are mounted in the same computer case, as occurs in many high power computers.
Another problem with fan assisted heat sink cooling devices is degradation of the fan motor over time. Such degradation is aggravated by heat being conducted from the heat sink into the fan motor.
Thus, it would be generally desirable to provide an apparatus and method which overcome these problems associated with cooling devices.
Disclosed herein is a cooling device primarily for cooling integrated circuits or other electronic devices during operation.
The cooling device may include a heat sink portion having a chamber therein. A fan, or other air movement device may be housed within the chamber. A plurality of slots, defining vanes therebetween, may extend between the chamber an d the exterior of the heat sink. The outer periphery of the heat sink portion may be formed with outwardly extending protrusions, leaving recessed areas between the protrusions. The protrusions may be sized and located so as to correspond to heat concentration areas on an electronic device package. The recessed areas, on the other hand may be located so as to correspond to areas on the electronic device package which are not heat concentration areas. In this manner, heat sink material may be concentrated adjacent to heat concentration areas where more heat removal is required. The overall mass and size of the heat sink portion may, thus, be reduced without significantly impairing the ability of the cooling device to remove heat from an electronic device.
The heat sink protrusions may, for example, be of generally circular shape. Alternatively, the protrusions may be formed having any other shape, such as a rectangular or a triangular shape. Although the protrusions may be formed having any shape, they may alternatively be referred to herein simply as xe2x80x9clobesxe2x80x9d.
The heat sink chamber may include a lower wall portion which is located beneath the fan blades when a fan is installed within the chamber. This lower wall portion may slope away from the fan blades in a radially outward direction. In this manner the distance between the fan blades and the chamber lower wall portion is increased in areas where the fan blades rotate at the highest velocity. It has been found that this increased distance results in reduced noise emission from the cooling device when the fan is in operation.
The heat sink fan chamber may include a wider portion at its upper end, thus causing at least a portion of the outer wall of the fan chamber to have an increased spacing from the fan blades. This increased spacing has also been found to reduce noise emission from the cooling device when the fan is in operation. The slots in the heat sink portion may either be radially oriented or may be offset slightly from the radial direction in order to further reduce noise emission.
The cooling device may be attached to an electronic component by providing either integrally formed attachment feet or by using a bracket arrangement. In the case where a bracket arrangement is used, the bracket may be either integrally formed with the heat sink portion or may be a separate assembly.
The heat sink portion may also be provided with an open space located beneath the base of the fan. This open space serves to insulate the motor of the fan from the heat sink base and, thus, reduce the amount of heat which transfers from the heat sink base to the fan motor. This, in turn, reduces the amount of heat-induced degradation and, thus, increases the life of the fan motor.